Merge branch 'sctp-rx-side-stream-reconf-asoc-reset-and-add-streams-and-response'

Merge branch 'sctp-rx-side-stream-reconf-asoc-reset-and-add-streams-and-response'

Xin Long says:

====================
sctp: add receiver-side procedures for stream reconf asoc reset and add streams and response

Patch 2/7, 4/7, 5/7, 6/7 are to implement the process of asoc reset request,
add streams requests and all kinds of responses.

Patch 1/7 and 3/7 are ahead of 2/7 and 4/7 to add two event notification
for asoc reset and add streams.

Patch 7/7 is the last patch for implementing rfc6525 sctp stream reconf
to add sysctl and sockopt interface for users to enable sctp stream reconf.

After this patchset, sctp stream reconf will be able to work as rfc6525.

v1->v2:
  - put these into a smaller group.
  - rename the titles of the commits and improve some changelogs.
  - improve sctp_chunk_lookup_strreset_param and reuse it in patch 4/7.
  - process addstrm outreq as the ack of in addstrm inreq if strreset_chunk
    is not NULL in patch 4/7.
  - remove the stream alloc when sending addstrm inreq, and the process in
    peer will response it by sending a addstrm out request back in patch 5/7.
  - adjust the process of addstrm in resp to fit in the codes that only alloc
    streams through addstrm outreq in patch 6/7.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>